JP5189711B1 - Optical film thickness measuring apparatus and thin film forming apparatus using optical film thickness measuring apparatus - Google Patents

Abstract

Provided is an optical film thickness measurement device that directly measures the film thickness of a product in real time without using a monitor substrate and measures the film thickness with high accuracy.
The optical film thickness measuring device includes a light projecting unit, a light receiving unit, an internal beam splitter in a plurality of substrate holding means that reflects measurement light to the substrate, and a closest internal beam splitter among the plurality of internal beam splitters. Internal light reflecting member that totally reflects measurement light, multiple external beam splitters that reflect measurement light from multiple internal beam splitters toward the light receiving unit, and measurement light from the light reflecting member is reflected toward the light receiving unit An external light reflecting member is provided. After the measurement light reflected by the internal beam splitter and the internal light reflecting member is transmitted through the substrate, it is reflected by the external beam splitter and the external light reflecting member and guided to the light receiving unit to receive the measurement light.
[Selection] Figure 2

Description

  The present invention relates to an optical film thickness measuring apparatus and a thin film forming apparatus using the optical film thickness measuring apparatus, and more particularly to an optical film thickness measuring apparatus and an optical type capable of directly measuring a film thickness of a product and measuring a film distribution. The present invention relates to a thin film forming apparatus using a film thickness measuring apparatus.

  Conventionally, in general, precision optical filters have been used for digital cameras, projectors, DVDs, etc., and PVD (physical vapor deposition) such as sputtering or vacuum deposition has been used for film formation of these precision optical filters. Yes. Further, chemical vapor deposition such as CVD is known as a technique for forming an optical thin film on the surface of a substrate.

  In the field of such a thin film forming technique, a carousel type rotation mechanism is known as one of rotation mechanisms of a substrate holding means for holding a substrate (substrate). In the carousel type rotation mechanism, a plurality of substrates (substrates) are held on the outer peripheral surface of a rotary drum (that is, a substrate holding means) having a circular or polygonal cross section, and in this state, the rotation axis is the center. The rotating drum is rotating. Thus, in the carousel type thin film forming apparatus, since the substrate (base) is held on the outer peripheral surface of the rotating drum, the substrate (base) stayed in one place while the rotating drum is rotating. It does not exist, and all the substrates (bases) rotate around the rotation axis.

  For this reason, in order to measure the optical characteristics of the thin film such as the film thickness by the optical method, it is necessary to stop the rotation of the rotating drum and then perform optical measurement on the substrate (base). In such a measuring method, the thin film forming process must be stopped every time the film thickness is measured, and thus there is a disadvantage that the thin film forming process takes time.

  In order to solve the inconvenience as described above, it is conceivable to optically measure the film thickness in real time with the rotating drum rotating. For example, a method of projecting measurement light from the outside of the rotating drum toward the substrate (base) and receiving reflected light reflected from the substrate (base) can be considered. However, in this method, since the rotating drum is rotating as described above, the angle of light incident on the substrate (base) changes at any time, and it is difficult to accurately measure the film thickness. .

  In order to solve the above-described problems, a film thickness measuring device that projects and receives light through the rotating shaft of a rotating drum that is a hollow shaft, and a thin film forming apparatus including the film thickness measuring device have been developed. Yes. The film thickness measuring device includes a rotary drum having a rotary shaft that is a hollow shaft, a total reflection mirror disposed in the rotation shaft, a total reflection mirror disposed on an axial extension of the rotation shaft, and a half mirror. A light source for irradiating measurement light to a total reflection mirror disposed on the extension of the rotation axis via a light receiver, and a light receiver for receiving reflected light from the total reflection mirror disposed on the extension of the rotation axis via the half mirror (For example, refer patent document 1).

  According to this film thickness measuring apparatus, the measurement light from the light source irradiates the total reflection mirror disposed on the rotation axis extension via the half mirror. The measurement light irradiated on the total reflection mirror in the rotating shaft is reflected on the measuring glass (monitor substrate) held on the rotating drum. On the other hand, the measurement light applied to the measurement glass (monitor substrate) is also reflected by the total reflection mirror. This reflected light is applied to the light receiver through the half mirror.

  As described above, according to the conventional thin film forming apparatus, the measurement light and the reflected light are guided through the rotating shaft of the rotating drum which is a hollow shaft, so that the measurement is performed in real time even though the rotating drum is rotating. It becomes possible to measure the film thickness of the glass.

  However, in this film thickness measuring apparatus, the measurement glass is irradiated with the measurement light and the reflected light from the measurement glass (monitor substrate) is reflected through a single total reflection mirror provided in the rotation axis. Therefore, measurement light and reflected light are introduced and extracted from the same end of the rotation axis. For this reason, the intensity of the measurement light or the reflected light may change due to shake of the rotation axis, vibration, or the like, and an error may occur in the obtained film thickness value.

  Therefore, in order to solve the above inconvenience, the present applicant has already proposed a film thickness measurement technique. The proposed technique includes a light projecting unit that projects measurement light from one side of the rotation axis toward the inside of the substrate holding unit, and a measurement light that is provided inside the substrate holding unit and is projected from the light projecting unit. A first light reflecting member that reflects the light reflected from the base body, a second light reflecting member that reflects the reflected light reflected from the base toward the other side of the rotation axis, A technology including a light receiving unit that receives reflected light reflected by the two light reflecting members, and a film thickness calculating unit that calculates the thickness of a thin film formed on the base based on the reflected light received by the light receiving unit. (Patent Document 2).

JP 2000-088531 A (pages 1 to 5, FIGS. 1 and 2) JP 2007-211311 A

  In the technique proposed in Patent Document 2 above, measurement light and reflected light are incident and emitted from different directions of the rotation axis, respectively, so that it is possible to obtain a highly accurate film thickness value with little error, and in particular, reflectivity. Even when measuring the film thickness of a thin film made of a low material, it is excellent in that it is expected to obtain a high film thickness value with high sensitivity.

  However, since the proposed technique uses a monitor substrate when measuring a plurality of substrates, the substrate disposed at different positions (positions different by 120 degrees) will be measured. In other words, since the monitor substrate (monitor glass) and the product substrate (workpiece substrate) to be formed are different in position or space, it is an indirect measurement, and the monitor substrate (monitor glass) and the product substrate to be formed (monitor glass). Therefore, the film thickness is measured by correcting with a predetermined parameter.

  An optical film thickness meter using a direct-view optical monitor is known for the indirect measurement. However, the optical film thickness meter with a direct-view optical monitor is generally compatible with a single product substrate (work substrate), and there are devices that target multiple product substrates. There wasn't.

Thus, when mass-producing and manufacturing an optical filter by PVD or the like, for example, in the case of sputtering or vapor deposition, a product substrate (work substrate) is arranged on a tram or dome, and this product substrate (work substrate) is placed on the product substrate. Although the film is formed, an optical filter with uniform performance can be obtained by making the film thickness uniform, making a prototype of the film, and correcting the correction plate.
For this purpose, the film distribution measurement is measured. However, an expensive film thickness meter using a plurality of optical fibers and a plurality of spectroscopes is used, which is complicated and expensive. There was an inconvenience.

  The present invention has been made in view of the above circumstances, and its object is to directly measure the film thickness of a product without using a monitor substrate, particularly in a thin film forming apparatus equipped with a carousel type rotation mechanism. It is possible to provide an optical film thickness measuring apparatus capable of measuring the film thickness of a thin film formed on a plurality of substrates arranged in the same row in real time with high accuracy.

Another object of the present invention is to provide a thin film forming apparatus using an optical film thickness measuring device capable of directly measuring a product, not a monitor substrate, and controlling the film thickness of the product.
Still another object of the present invention is to provide an optical film thickness measuring apparatus and an optical system that can control the film thickness while measuring the film thickness of the products on the upper and lower stages of the rotating drum using one optical system. The object is to provide a thin film forming apparatus using a film thickness measuring apparatus.

According to the optical film thickness measuring apparatus of the present invention, the above-mentioned problem is an optical film thickness measuring apparatus for an optical thin film forming apparatus provided with a rotating substrate holding means, wherein the rotating substrate holding means is rotated. Provided inside the base body holding means, a light projecting section for projecting measurement light from one side of the axis toward the inside of the base body holding means, a light receiving section for receiving measurement light from the light projecting section, and And a plurality of internal beam splitters that reflect the measurement light projected from the light projecting unit to the substrate, and the inner beam splitter that is provided inside the substrate holding means and that is the closest of the plurality of internal beam splitters An internal light reflecting member that totally reflects measurement light from the substrate, and a plurality of external beams that are provided outside the substrate holding means and reflect the measurement light from the plurality of internal beam splitters toward the light receiving unit. And liters, with provided outside of the substrate holding means, and an external light reflecting member for reflecting the measurement light from the internal light reflecting member to the light receiving portion, said plurality of internal beam splitter and the internal After allowing the measurement light reflected by the light reflecting member to pass through the substrate, the measurement light is reflected by the plurality of external beam splitters and the external light reflecting member and guided to the light receiving unit, and the measurement light is received. Solved.

  Because of this configuration, it is possible to directly measure the film thickness of a product without using a monitor substrate, and the film thickness of a thin film formed on a plurality of substrates arranged in the same row can be measured in real time. In addition, it is possible to measure with high accuracy. In addition, since one optical system is used and no movable optical component is used, the reliability is high and the maintainability is improved.

At this time, the rotation axis of the substrate holding means is located in a hollow rotation shaft constituting the center of the substrate holding means, and the internal beam splitter and the internal light reflecting member are disposed in the rotation shaft. It is preferable that the wall surface of the rotating shaft body is configured to allow the reflected measurement light to pass therethrough. Further, the measurement light reflected by the internal beam splitter and the internal light reflecting member is made to have substantially the same amount of light.
In this way, the same measurement sensitivity (accuracy) is obtained when the same amount of measurement light is irradiated onto the substrate (substrate) that is each product.

  In addition, it is preferable to provide a film thickness calculator that calculates the film thickness of the thin film formed on the substrate based on the measurement light received by the light receiver.

Further, it is preferable that the plurality of external beam splitters and the external light reflecting member are covered with a hollow housing, and a portion of the housing where the measurement light is incident is configured to be able to pass the measurement light.
If comprised in this way, a contamination, etc. of an external beam splitter and an external light reflection member can be prevented, and maintainability improves more.

Furthermore, it is preferable that a shutter device is provided between the plurality of external beam splitters and the external light reflecting member.
By using the shutter device in this way, it is possible to block the optical path, and when the substrate (substrate) that is the object to be measured is not mounted, it can be removed from the object to be measured.

In addition, it is preferable that the light projecting unit and the light receiving unit are provided in the same direction or on the same surface of the optical thin film forming apparatus.
Thus, when the light projecting unit and the light receiving unit are provided in the same direction or the same surface position of the optical thin film forming apparatus, for example, on the upper surface of the substrate holding unit, the light projecting unit and the light receiving unit are in the same direction. Or since it is the position of the same surface, installation etc. of the said light projection part and the said light-receiving part are easy, and attachment and maintenance property of an optical film thickness measuring device improve. In particular, since it is located on the upper surface side, various operations such as mounting and maintenance become easier than arrangement on the lower surface side.

In addition, the light projecting unit and the light receiving unit may be configured to be provided in the opposite direction of the optical thin film forming apparatus or in the position of the opposite surface.
If comprised in this way, since the position of a light projection part and a light-receiving part can be provided in the other side like a conventional apparatus, it will become possible to prevent changing the layout of a prior art apparatus.

According to the thin film forming apparatus of the present invention, the above-described problem is that a substrate holding means capable of rotating around a rotation axis while holding a substrate disposed in a vacuum vessel, and a film raw material for forming a thin film in the vacuum vessel 8. A rotary type thin film forming apparatus for forming a thin film, comprising: a film raw material supply means for supplying a material; and a film forming process region for forming a thin film on the substrate. This is solved by using the optical film thickness measuring device according to one item.
According to the thin film forming apparatus according to the present invention, it is possible to provide an apparatus utilizing the characteristics of the optical film thickness measuring apparatus.

  As described above, according to the optical film thickness measuring apparatus and the thin film forming apparatus of the present invention, the plurality of beam splitters and the total reflection mirrors are disposed along the rotation axis of the substrate holding means. Since it is possible to directly measure the film thicknesses of the substrates (substrates) to be a plurality of products arranged along the rotation axis, it is an actual product by measuring these substrates. The film thickness of the substrate (substrate) can be measured, and the film thickness of the product itself can be directly controlled instead of the monitor substrate.

According to the present invention, the film thickness of a product can be directly measured without using a monitor substrate, and the film thickness of a thin film formed on a plurality of substrates arranged in the same row can be increased in real time. It becomes possible to measure with accuracy.
In addition, when satisfying the performance required for an optical film thickness meter and forming a thin film, the substrate (product substrate) attached to the rotating substrate holding means can be directly measured. Using the optical film thickness measuring device and the optical film thickness measuring device that can obtain the same measurement sensitivity (accuracy) and can control the film thickness of products in multiple stages above and below the rotating drum. The thin film forming apparatus can be provided. In particular, since no movable optical components are used, the reliability is high, the maintainability is improved, and the cost including the maintenance can be reduced.

It is the section explanatory view which looked at the optical film thickness measuring device and thin film forming device concerning the embodiment of the present invention from the upper part. It is sectional explanatory drawing which looked at the thin film forming apparatus of FIG. 1 in the arrow AA direction. FIG. 3 is a partial cross-sectional perspective view of the rotating drum of FIG. 2 as viewed obliquely from above. It is a fragmentary sectional perspective view similar to FIG. 3 which shows 3rd Embodiment. It is a cross-sectional explanatory drawing similar to FIG. 2 which shows the other example of 3rd Embodiment. FIG. 6 is a partial cross-sectional perspective view of the rotating drum of FIG. 5 as viewed obliquely from above. It is sectional explanatory drawing similar to FIG. 2 which shows the other example of 5th Embodiment. It is explanatory drawing which shows the example of arrangement | positioning of a light projection lens. It is explanatory drawing of a mirror unit. It is explanatory drawing of a mirror unit. It is a block diagram which shows the functional structure of the optical film thickness measuring apparatus and thin film forming apparatus which concern on each embodiment of this invention. It is sectional explanatory drawing similar to FIG. 2 which shows other embodiment. It is explanatory drawing of the basic composition of the optical film thickness measuring device in the direction where a light projection part and a light-receiving part are the same. It is explanatory drawing of the basic composition of the optical film thickness measuring device in the direction where a light projection part and a light-receiving part are opposite. It is explanatory drawing of the calculation method of the output light of FIG.13 and FIG.14, and the relative output comparison of light. It is a figure which shows the output from the base | substrate (board | substrate) in 1st Embodiment. It is a figure which shows the output from the base | substrate (board | substrate) in 2nd Embodiment. It is a figure which shows the output from the base | substrate (board | substrate) in 3rd Embodiment. It is a figure which shows the output from the base | substrate (board | substrate) in 4th Embodiment.

DESCRIPTION OF SYMBOLS 1 Thin film forming apparatus 10 Processing container 11 Vacuum container 11a Thin film forming chamber 11b Load lock chamber 11c, 11d Door 13 Rotating drum (base | substrate holding means)
13a Rotating shaft 13b, 17a Gear 13c Opening 14 Partition wall 15 Vacuum pump 16a, 16b Piping 17 Rotating drum drive motor 20 Sputtering means 22a, 22b Target 24a AC power supply 30 Sputtering gas supply means 31, 33 Mass flow controller 32 Sputtering gas cylinder 34 Reactivity Gas cylinder 35 Piping 35a, 35b Correction plate drive motor 36a, 36b, 36c Film thickness correction plate 40 Plasma generating means 41 Case body 42 Derivative plate 43 Antenna 44 Matching box 45 High frequency power supply 50 Reactive gas supply means 51 Oxygen gas cylinder 52, 54 Mass flow Controller 53 Argon gas cylinder 55 Pipe 60 Optical film thickness measuring device 61 Light source 61a Light emitting element 61b Filter 62 Light projecting optical fiber 63 Light projecting head 64 Light projecting side condensing lens 65a Beam splitter 65b Second beam splitter 65c First total reflection mirror 66a Third beam splitter 66b Fourth beam splitter 66c Second total reflection mirror 66k Total reflection mirrors 66l and 66m Beam splitter 67 Light receiving side optical fiber 68 Light receiving side condensing lens 69 Light receiving head 71 Spectrometer 71a Light receiving element 71b Spectroscopic element 80 Film thickness calculation computer 81 CPU
82 Memory 83 Hard Disk 84 I / O Motor 83a Film Thickness Correlation Data 83b Film Thickness Calculation Program 90 Film Thickness Control Device 91 Film Thickness Control Signal Generation Unit 100a, 100b, 100c Optical Path Switching Shutter 101 Drive Unit 102a, 102b, 102c Shielding Plate 160 Cylindrical bodies 165a to 165d Beam splitters (BS1 to BS4)
166a to 166d Beam splitter (BS5 to BS8)
165e, 166e Total reflection mirror V Valve S Substrate (substrate)

  Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. Note that the members, arrangements, and the like described below are not limited to the present invention, and various modifications can be made in accordance with the spirit of the present invention.

  1 to 19 relate to an embodiment of the present invention, FIG. 1 is a cross-sectional explanatory view of the optical film thickness measuring device and the thin film forming device as viewed from above, and FIG. 2 is an arrow of the thin film forming device of FIG. FIG. 3 is a partial cross-sectional perspective view of the rotary drum of FIG. 2 viewed obliquely from above, and FIG. 4 is a partial cross-sectional perspective view similar to FIG. 3 showing the third embodiment. FIG. 5 is a cross-sectional explanatory view similar to FIG. 2 showing another example of the third embodiment, FIG. 6 is a partial cross-sectional perspective view of the rotating drum of FIG. 5 viewed obliquely from above, and FIG. FIG. 8 is an explanatory view showing an example of the arrangement of a projection lens, FIGS. 9 and 10 are explanatory views of a mirror unit, and FIG. 11 is an optical film according to each embodiment. FIG. 12 is a block diagram showing the functional configuration of the thickness measuring device and the thin film forming device, FIG. 12 is a cross-sectional explanatory view similar to FIG. 3 is an explanatory diagram of the basic configuration of the optical film thickness measuring device in the same direction of the light projecting unit and the light receiving unit, and FIG. 14 is the basic configuration of the optical film thickness measuring device in the opposite direction of the light projecting unit and the light receiving unit. FIG. 15 is an explanatory diagram of the output light calculation method and the relative light output comparison of FIGS. 13 and 14, FIG. 16 is a diagram showing the output from the substrate (substrate) in the first embodiment, and FIG. The figure which shows the output from the base | substrate (board | substrate) in 2nd Embodiment, FIG. 18 is the figure which shows the output from the base | substrate (board | substrate) in 3rd Embodiment, FIG. 19 shows the output from the base | substrate (board | substrate) in 4th Embodiment. FIG.

  In the thin film forming apparatus 1 of the present embodiment, a sputtering process for depositing a thin film considerably thinner than the target film thickness on the substrate surface by sputtering the target and depositing the film raw material on the substrate surface, and this film raw material An intermediate thin film is formed on the substrate surface by a plasma treatment that converts the composition of the thin film by performing a treatment such as oxidation on the substrate, and by repeating this sputtering treatment and the plasma treatment multiple times, a plurality of intermediate thin films are laminated. A final thin film having a target film thickness is formed on the substrate surface.

  Specifically, an intermediate thin film having an average film thickness of about 0.01 to 1.5 nm after composition conversion is formed on the substrate surface by sputtering treatment and plasma treatment, and is repeated for each rotation of the rotating drum. An intermediate thin film is laminated to form a final thin film having a target film thickness of several nm to several hundred nm.

  As shown in FIGS. 1 and 2, the thin film forming apparatus 1 includes a processing vessel 10 including a vacuum vessel 11 and a rotating drum 13, a sputtering unit 20, a sputtering gas supply unit 30, a plasma generation unit 40, a reactivity. The gas supply means 50 and the optical film thickness measuring device 60 are main components. In the figure, the sputtering means 20 is indicated by a broken line, the sputtering gas supply means 30 is indicated by a one-dot chain line, the plasma generating means 40 is indicated by a broken line, and the reactive gas supply means 50 is indicated by a two-dot chain line.

  In the reaction process, a film raw material adhering to the surface of the substrate (substrate) S in the film forming process is subjected to plasma treatment by the plasma generating means 40, and an intermediate thin film composed of a complete reaction product or an incomplete reaction product of the film raw material. Is forming.

  The plasma generating means 40 includes a case body 41, a dielectric plate 42, an antenna 43, a matching box 44, and a high frequency power supply 45. The case body 41 has a shape that closes the opening formed in the wall surface of the vacuum vessel 11, is fixed so as to close the opening of the vacuum vessel 11, and the case body 41 is fixed to the wall surface of the vacuum vessel 11, The plasma generating means 40 is attached to the wall surface of the vacuum vessel 11.

The reactive gas supply means 50 includes an oxygen gas cylinder 51 that stores oxygen gas, a mass flow controller 52 that adjusts the flow rate of the oxygen gas supplied from the oxygen gas cylinder 51, an argon gas cylinder 53 that stores argon gas, and an argon gas cylinder. Main components are a mass flow controller 54 for adjusting the flow rate of argon gas supplied from 53 and a pipe 55 for introducing a mixed gas composed of oxygen gas and argon gas into the reaction process region.
Then, the film raw material adhering to the surface of the substrate (substrate) S by sputtering or the like is plasma-processed by the plasma generating means 40 to form an intermediate thin film made of a complete reaction product or an incomplete reaction product of the film raw material material. .

  When power is supplied from the high frequency power supply 45 to the antenna 43 in a state where oxygen gas is introduced into the reaction process region from the oxygen gas cylinder 51 and the argon gas cylinder 53 through the introduction port of the pipe 55, the antenna 43 in the reaction process region faces the antenna 43. Plasma is generated in the region. This plasma oxidizes silicon (Si) and incomplete oxides of silicon (SiOx (where 0 <x <2)) in the film raw material formed on the surface of the substrate (substrate) S, thereby producing silicon. The intermediate thin film is formed from a complete oxide (SiO 2) or an incomplete oxide (SiO x (where 0 <x <2)).

  Next, the optical film thickness measuring device 60 according to the embodiment of the present invention will be described. The optical film thickness measuring device 60 measures the film thickness of a thin film formed on the surface of a substrate (substrate) S. In the present embodiment, as shown in FIGS. 2 to 7 and 12, the optical film thickness measuring device 60 includes an emission side that emits measurement light, and a light reception side of measurement light that has passed through the substrate (substrate) S. It has.

FIG. 8 is an explanatory view showing an arrangement example of the light projecting lens on the exit side. On the exit side, the light source 61 that emits the measurement light, the light projecting optical fiber 62 that transmits the measurement light from the light source 61, and the light projection The measurement light transmitted through the optical fiber 62 is guided to the light projecting head 63.
The light projecting head 63 emits measurement light to the first beam splitter (BS1) 65a, the second beam splitter (BS2) 65b, and the first total reflection mirror 65c arranged in the rotation axis. The light projecting side condensing lens 64 converges the measurement light from the light projecting head 63.

  9 and 10 are explanatory views of the mirror unit. FIG. 9 is a view showing a state in which the antifouling shield is attached, and FIG. 10 is an explanatory view of the mirror unit with the antifouling shield removed. The total reflection mirror shown in FIGS. 9 and 10 is a dielectric mirror.

  In the present embodiment, a first beam splitter (BS1) 65a that transmits part of the measurement light from the light projecting head 63 and guides part of the measurement light to a product base (substrate) S as a base, and the first beam splitter ( BS1) a second beam splitter (BS2) 65b that transmits a part of the measurement light that has passed through 65a and guides a part of the measurement light to the product substrate (substrate) S, and the second beam splitter (BS2) 65b. And a first total reflection mirror 65c that reflects the measurement light transmitted through the first reflection mirror 65c. A light projecting optical fiber 62 is connected to the light source 61, one end of the light projecting optical fiber 62 is introduced into the light source 61, and the measurement light transmitted through the filter of the light source 61 is incident on the end face of the light projecting head 63. It is arranged to be led to.

The light projecting head 63 is disposed outside the vacuum vessel 11 above the rotation shaft 13a (FIG. 2). The first beam splitter (BS1) 65a and the second beam splitter (BS2) disposed inside the rotation shaft 13a. ) 65b and the first total reflection mirror 65c are directed, and the measurement light emitted from the light projecting head 63 is incident on one end of the rotary shaft 13a, passes through the rotary shaft 13a along the axial direction, and passes through the first axis. Irradiated to the beam splitter (BS1) 65a, the second beam splitter (BS2) 65b, and the first total reflection mirror 65c.
The first beam splitter (BS1) 65a, the second beam splitter (BS2) 65b, and the first total reflection mirror 65c are configured so as to be fixed at predetermined positions inside the rotation shaft 13a. It is configured to be adjustable.

  The light receiving side includes a third beam splitter (BS3) 66a, a fourth beam splitter (BS4) 66b, and a second total reflection mirror 66c that reflect the measurement light transmitted through the substrate (substrate) S toward the light receiving head 69. A light receiving side condensing lens 68 for converging the measurement light transmitted or reflected by the third beam splitter (BS3) 66a, the fourth beam splitter (BS4) 66b, and the second total reflection mirror 66c, a light receiving head 69, and a light receiving head The light receiving side optical fiber 67 that transmits the measurement light received by 69 and the spectroscopic measurement device 71 that splits the measurement light transmitted by the light receiving side optical fiber 67 are provided as main components. In other words, the measurement light transmitted through or reflected by the third beam splitter (BS3) 66a, the fourth beam splitter (BS4) 66b, and the second total reflection mirror 66c and transmitted through the substrate (substrate) S is transferred to the third beam splitter (BS3). BS3) 66a, the fourth beam splitter (BS4) 66b, and the second total reflection mirror 66c are reflected or transmitted and guided to the spectrometer 71 as measurement light.

The light source 61, the light projecting optical fiber 62, and the light projecting head 63 correspond to the light projecting unit of the present invention. Further, the light receiving head 69, the light receiving side optical fiber 67, and the spectroscopic measurement device 71 correspond to a light receiving unit. The first total reflection mirror 65c corresponds to an internal light reflection member, and the second total reflection mirror 66c corresponds to an external light reflection member.
The third beam splitter (BS3) 66a, the fourth beam splitter (BS4) 66b, and the second total reflection mirror 66c on the light receiving side are arranged at predetermined positions by a holding member (not shown, for example, a bar-like member having any cross-sectional shape). In this case, the angular position can be adjusted.

Reference numerals 100a to 100c denote optical path switching shutters, which include a drive unit 101 and shielding plates 102a to 102c.
The optical path switching shutters 100a to 100c use servo motors (other actuators or the like) as the drive unit 101. The shields 102a to 102c are moved by the drive unit 101, and the shield plates 102a to 102c are measured from the emission side. The light is configured to move between a position where the third beam splitter (BS3) 66a, the fourth beam splitter (BS4) 66b and the second total reflection mirror 66c are blocked and a position where the light is not blocked. The shielding plates 102a to 102c may be configured to block the measurement light, and the shape and the like are not particularly limited. A driving unit 101 is attached to the outside of the vacuum vessel 11 as a driving source in the optical path switching shutters 100a to 100c.

  The shielding plates 102a to 102c are configured to move to positions where the measurement light from the beam splitters (BS1, BS2) 65a and 65b and the first reflection mirror 65c is not a blocking position. The shielding plates 102a to 102c also serve to prevent dirt. The drive unit 101 is disposed outside the vacuum chamber.

  The first total reflection mirror 65c and the second total reflection mirror 66c are members formed by forming a thin film such as aluminum on the surface of a substrate such as glass, and have a high reflection of almost 100% at least at the wavelength of measurement light. Have a rate. The total reflection mirror of the present embodiment is configured by a substantially square plate-like member. The total reflection mirror is disposed inside the hollow body of the rotating shaft 13a, and is fixed to the inner wall surface of the rotating shaft 13a by welding or screwing.

  The light source 61 of the present embodiment uses a halogen lamp, a white LED, or the like, and is an apparatus that is installed outside the vacuum vessel 11 and emits measurement light for film thickness measurement. As shown in FIG. 11, the light source 61 transmits light from a power source (not shown) and emits light, and transmits light in a specific wavelength region out of light emitted from the light emitting element 61a. A filter 61b is provided.

  An opening 13c in which a part of the side wall is notched is formed in the central portion of the rotating shaft 13a, and the measurement light reflected from the beam splitters (BS1, BS2) 65a and 65b and the first total reflection mirror 65c is the opening 13c. The substrate (substrate) S held on the rotary drum 13 is irradiated. In addition, although the example which formed the opening 13c is shown in this embodiment, it can also be comprised so that it may seal using the glass material which can permeate | transmit completely.

  As described above, the present invention does not require a monitor substrate for film thickness measurement as in the prior art, and directly measures the film thickness of the product substrate itself. There is no need to select a transparent glass material as the substrate, or a plastic as a material that transmits the wavelength of the measurement light with high transmittance.

The measurement light applied to the substrate (substrate) S from the emission side is divided into measurement light directed toward the substrate (substrate) S by the beam splitter and transmitted measurement light, and finally reflected by the total reflection mirror.
That is, a part of the measurement light irradiated to the first beam splitter (BS1) 65a is reflected and incident from the back surface side of the base body (substrate) S (that is, the rotating shaft 13a side). Transparent inside. The transmitted measurement light without being reflected by the first beam splitter (BS1) 65a is guided to the next second beam splitter (BS2) 65b, and a part of the reflected light is reflected by the second beam splitter (BS2) 65b. Then, the light enters from the back surface side of the base body (substrate) S (that is, the rotating shaft 13a side) and passes through the base body (substrate) S. Further, the transmitted measurement light without being reflected by the second beam splitter (BS2) 65b is guided to the first total reflection mirror 65c. The first total reflection mirror 65c is composed of a member having a high reflectance of approximately 100% at the wavelength of the measurement light. The measurement light emitted from the emission side is received by the light receiving side.

  Similar to the light projecting head 63, the light receiving head 69 is disposed outside the vacuum vessel 11 on the upper side of the rotating shaft 13a (FIG. 2), and reflects the measurement irradiated from the emission side to guide it to the light receiving head 69. The third beam splitter (BS3) 66a, the fourth beam splitter (BS4) 66b, and the second total reflection mirror 66c are arranged at predetermined positions on the outer peripheral side of the rotary drum 13 arranged in the vacuum vessel 11. In the present embodiment, as shown in FIG. 2, it is disposed at a position farthest from the sputtering means 20 and the plasma generation means 40. Thereby, it is configured so as not to be easily influenced by the sputtering means 20 and the plasma generation means 40.

  The light receiving head 69 is disposed at a position where measurement light reflected by the first beam splitter (BS1) 65a, the second beam splitter (BS2) 65b, and the first total reflection mirror 65c is incident. One end of the optical fiber 67 is connected, and the other end is connected to the spectroscopic measurement device 71. The measurement light transmitted through the substrate (substrate) S is reflected by the third beam splitter (BS3) 66a, the fourth beam splitter (BS4) 66b, and the second total reflection mirror 66c, and is converged on the light receiving side condenser lens 68. After that, the light enters the light receiving head 69. The incident measurement light is guided to the light receiving side optical fiber 67 and introduced into the spectroscopic measurement device 71.

  As described above, since both the light projecting head 63 and the light receiving head 69 are provided outside the vacuum vessel 11, the optical fiber generated when the light projecting head 63 and the light receiving head 69 are arranged inside the rotating drum 13 is twisted by the rotation of the rotating drum 13. It is possible to prevent the possibility of tangling. In addition, since the rotary drum 13 is heated during the film formation process and becomes a high temperature because it is outside the vacuum vessel 11, there is no inconvenience that the light projecting head and the light receiving head are thermally denatured by this heat. As described above, according to the present invention, it is possible to prevent the twisting and entanglement of the optical fiber and the influence of heat generated in the film formation process, and to perform stable film thickness measurement.

  The spectroscopic measurement device 71 is a device that measures the intensity of light having a predetermined wavelength in the reflected light, and has the same configuration as a known spectroscopic measurement device used in film thickness measurement. That is, as shown in FIG. 11, the spectroscopic measurement device 71 receives the light transmitted through the spectroscopic element 71b and the spectroscopic element 71b that transmits light in a predetermined wavelength region of the reflected light, and responds to the intensity of the light. A light receiving element 71a for outputting the measured current value.

  The spectroscopic element 71b is formed of a member including a diffraction grating such as grating, and transmits light in a predetermined wavelength region. In the present embodiment, the spectroscopic element 71b transmits the wavelength of the measurement light with a transmittance of at least approximately 100%. The light transmitted through the spectroscopic element 71b is guided to the light receiving element 71a. The light receiving element 71a is composed of a semiconductor element such as a photodiode, for example, and an element obtained by bonding a p-type and an n-type semiconductor, for example, is brought in. When light strikes the p-type and n-type joint surfaces, a current corresponding to the intensity of the light is generated, and this current is converted into a digital signal by an A / D conversion circuit in the spectroscopic measurement device 71 for spectroscopic measurement. The data is output from the apparatus 71 to a film thickness calculation computer 80 described later.

  The film thickness calculation computer 80 is means for calculating the film thickness of the thin film formed on the substrate (substrate) S based on the intensity of the measurement light measured by the spectrometer 71. As shown in FIG. 11, the film thickness calculation computer 80 receives signals between a CPU 81 as calculation means, a hard disk 83 and memory (specifically ROM, RAM) 82 as storage means, and an external device or the like. And an I / O port 84 as an input / output port when transmitting / receiving data. The film thickness calculation computer 80 corresponds to the film thickness calculation unit of the present invention.

  A spectroscopic measurement device 71 is electrically connected to the film thickness calculation computer 80, and an intensity signal of the measurement light digitized by the spectroscopic measurement device 71 is sent to the I / O port 84 of the film thickness calculation computer 80. Then, the data is input to a hard disk 83 and a memory (specifically, ROM, RAM) 82 as storage means. For example, the hard disk 83 is transmitted from the spectroscopic measurement device 71 and the film thickness correlation data 83a in which the correlation between the change in the intensity of the measurement light and the film thickness of the thin film formed on the substrate (substrate) S is stored. A film thickness calculation program 83b for calculating the film thickness based on the intensity signal of the measurement light and the film thickness correlation data 83a is stored. The film thickness correlation data 83a and the film thickness calculation program 83b can be configured to be stored in a RAM, a ROM, or the like.

  The principle of measuring the film thickness with the film thickness calculation computer 80 will be described below. The measurement light applied to the substrate (substrate) S is reflected at the boundary between the substrate (substrate) S and the thin film and at the boundary between the thin film and the vacuum vessel side. At this time, these reflected lights interfere with each other, and the intensity of the reflected light changes.

  Here, there is a predetermined correlation between the intensity of the reflected light or transmitted light of the thin film and the film thickness. More specifically, assuming that the refractive index n, the wavelength λ, and the geometric film thickness d of the thin film, the intensity of the reflected light periodically peaks every time the optical film thickness nd becomes an integral multiple of λ / 4. It is known. Since there is a predetermined correlation between the peak height (peak value P) and the refractive index, the refractive index can be obtained by obtaining the peak value P. That is, the peak value P is obtained by measuring the intensity of the reflected light, and the geometric film thickness d is calculated from the optical film thickness nd based on the refractive index n and the wavelength λ of the peak value P. It becomes possible.

  The film thickness calculation computer 80 stores the wavelength λ of the measurement light as a set value in advance. Then, the film thickness calculation program 83b calculates the refractive index n by obtaining the height of the peak value P from the intensity signal of the reflected light transmitted from the spectroscopic measurement device 71. Further, the geometric film thickness d is calculated based on the refractive index n and the wavelength λ.

  The film thickness calculation computer 80 is electrically connected to the film thickness control device 90. The film thickness controller 90 includes an arithmetic unit such as an MPU, a storage unit such as a ROM and a RAM, and an input / output port that transmits and receives electrical signals to and from other devices. A film thickness (that is, a geometric film thickness d) measured by the film thickness calculation computer 80 is input to the film thickness controller 90. The film thickness control device 90 includes a film thickness control signal generation unit 91. By adjusting the film formation rate and the film formation time based on the film thickness signal from the film thickness control signal generation unit 91, the film thickness control signal generation unit 91 is provided. Control the thickness.

  Specifically, the film thickness control device 90 is configured to increase or decrease the power supplied from the AC power source 24a of the sputtering means 20 to the targets 22a and 22b based on the film thickness acquired by the film thickness calculation computer 80, and the sputtering gas supply means. 30 by any one or more of the following methods: increase / decrease in the supply amount of sputtering gas and reactive gas supplied to the film forming process area 30 and advance / retreat of the film thickness correction plates 36a, 36b by the correction plate drive motors 35a, 35b, Adjust the deposition rate. Reference numeral 36c denotes a film thickness correction plate, and the film thickness controller 90 corresponds to a film thickness adjusting means.

  In addition, the film thickness can be adjusted by adjusting the film formation time. That is, when the film thickness of the substrate (substrate) S acquired by the film thickness calculation computer 80 is smaller than the preset film thickness, the film thickness controller 90 does not end the film formation at a predetermined film formation end time. The film thickness is increased to a preset film thickness so as to extend the film formation time. On the other hand, when the film thickness of the substrate (substrate) S acquired by the film thickness calculation computer 80 is larger than the preset film thickness, the film thickness controller 90 forms the film before a predetermined film formation end time. The film formation time is shortened by completing the process, and the film formation is completed with a preset film thickness. In addition, these film thickness control methods may adjust a film thickness using only any one, and may adjust a film thickness combining several methods.

Thus, the optical film thickness meter of this embodiment can automatically calculate the rate during film formation and control the film thickness. Then, by sending a control signal to the automatic correction plate mechanism, the film thickness and quality control of the optical thin film product can be performed. For example, in the case of the stop photometry method, the control can be performed by analyzing the film thickness from the measurement result of the spectral characteristics of the substrate (substrate) S.
On the other hand, in photometry during rotation, the amount of light transmitted through the substrate (substrate) S is measured, and film thickness control can be realized.

  First, the basic configuration of the present invention is configured as shown in FIGS. That is, in the case of one branch: mirror 1 and mirror 2 are used between light projection and light reception. In the case of two branches: Two BSs (BS1, BS2) and two mirrors (mirror 1, mirror 2) are used between light projection and light reception. In the case of three branches: Four BSs (BS1 to BS4) and two mirrors (mirror 1 and mirror 2) are used. In the case of four branches: Six BSs (BS1 to BS6) and two mirrors (mirror 1 and mirror 2) are used. In the case of five branches: eight BSs (BS1 to BS8) and two mirrors (mirror 1 and mirror 2) are used.

  In the case where the light projecting unit and the light receiving unit are in the same direction or in different directions, the mirror and the BS are arranged in the same direction except in the case of one branch. In the case of a mirror in the direction, it is always placed at the opposite position at the last reflecting position, and in the opposite direction, the mirror on the light receiving unit side is fixed at the position where it was first placed and placed on the light projecting side. The mirror is arranged at a position that sequentially moves downward for each branch.

  Further, the light output unit and the light receiving unit calculate the output light in the same direction as the relative light output P = (100% / n) ^ 2, where P = 100% for one branch and n = for two branches. 2 P = 25%, 3 branches are calculated as n = 3 P = 11.1%.

Similarly, the calculation method of the output light in the opposite direction between the light projecting unit and the light receiving unit is a light relative output P = (50%) ^ n, where P = 100% for one branch and n = 2 for two branches. P = 25%, 3 branches are calculated as n = 3 P = 12.5%.
The relative output comparison in the case of each branch is as shown in the table of FIG.

Therefore, the first to fourth embodiments will be specifically described with reference to FIGS. 16 to 19.
<First Embodiment>
The first embodiment is an example in which aluminum reflection mirrors having a reflectance of 90% are used as the first and second total reflection mirrors 65c and 66c. The first beam splitter (BS1) 65a is 18/82 for reflection / transmission, the second beam splitter (BS2) 65b is 45/55 for reflection / transmission, the first total reflection mirror 65c and the second total reflection mirror 66c. As an aluminum reflecting mirror, the reflectivity is 90%, and the third beam splitter (BS3) 66a and the fourth beam splitter (BS4) 66b are 50/50 for reflection / transmission. The transmittance (efficiency) of the measurement light of the product substrate (substrate) S is 9%, 9.2%, and 9.1%, respectively. The optical path can be switched by the optical path switching shutters 100a to 100c.

The procedure for measuring the transmittance of the base (substrate) S in the upper, middle and lower drums is as follows.
Upper stage Middle stage Lower stage shielding plate 102a off on on
Shield plate 102b on off on
Shielding plate 102c on on off
Alternatively, the average transmittance of the substrate (substrate) S of the product is T (average) = (T1 + T2 + T3) / 3, and the shielding plates 102a, 102b, and 102c are all in the off state.

More specifically, the procedure for measuring the transmittance of the substrate (substrate) S of the lower product through the substrate (substrate) S of the middle product from the substrate (substrate) S of the upper product is as follows.
Base product (substrate) S of upper product -Substance (substrate) S of middle product -Substrate (substrate) S of lower product
Optical path switching shutter 100a → ON → OFF → ON
Optical path switching shutter 100b → OFF → ON → OFF
Optical path switching shutter 100c → OFF → OFF → OFF
And
Dark current measurement
Dark current 1: the optical path switching shutter 100a is on and the optical path switching shutters 100b and 100c are off.
Dark current 2: the optical path switching shutter 100b is on and the optical path switching shutters 100a and 100c are off.
Dark current 3: the optical path switching shutter 100b is on and the optical path switching shutters 100a and 100b are off.
The average transmittance measurement of the substrate (substrate) S of the product is T (average) = (T1 + T2 + T3) / 3, and the three optical path switching shutters 100a to 100c are off.
The relative light intensity% of the substrate (substrate) S of the upper product, the substrate (substrate) S of the middle product, and the substrate (substrate) S of the lower product in the first embodiment is as shown in FIG. The measuring light can be distributed very evenly.

Second Embodiment
17 includes a first beam splitter (BS1) 65a, a third beam splitter (BS3) 66a, and a dielectric mirror according to the second embodiment. As shown in FIG. 17, the reflection / transmission is 33.3 / 66.7. Is used. The second beam splitter (BS2) 65b and the fourth beam splitter (BS4) 66b are 50/50 for reflection / transmission. The first total reflection mirror 65c and the second total reflection mirror 66c are dielectric mirrors having a reflectance of 99.9% (that is, in the first embodiment, the first and second total reflection mirrors 65c are used). , 66c is an example in which an aluminum mirror having a reflectance of 90% is used. On the other hand, in the second embodiment, the first and second total reflection mirrors 65c, 66c are dielectrics having a reflectance of 99.9%. The use of mirrors is a different feature).
As described above, the second embodiment is a multi-work photometric optical system. The first beam splitter (BS1) 65a is 33.3 / 66.7 for reflection / transmission, and the second beam splitter (BS2) 65b is Regarding reflection / transmission, 50/50, the first total reflection mirror 65c, and the second total reflection mirror 66c are 99.9% of the derivative. The third beam splitter (BS4) 66a uses 33.3 / 66.7 for reflection / transmission, and the fourth beam splitter (BS4) 66b uses 50/50 for reflection / transmission. The transmittance (efficiency) of the measurement light of the product substrate (substrate) S is 11%, 11%, and 11%. The optical path can be switched by the optical path switching shutters 100a to 100c.
The relative light intensity% of the base (substrate) S of the upper product, the base (substrate) S of the middle product, and the base (substrate) S of the lower product in the second embodiment is as shown in FIG.

<Third Embodiment>
FIGS. 4 and 18 are partial sectional perspective views similar to FIG. 3 showing the third embodiment. In this embodiment, an example in which the shutter device is not used is shown, and an example of five branches is shown. is there. In addition, the same code | symbol is attached | subjected to the same material, the same member, the same arrangement | positioning, etc. as the said embodiment, and the description is abbreviate | omitted.
In the present embodiment, an example is shown in which four beam splitters (165a to 165d, 166a to 166d) are used on the emission side and the light reception side, respectively, and one total reflection mirror is used (165e and 166e). If comprised like this example, all the film thicknesses of the base | substrate (substrate | substrate) S attached to the holding | maintenance part can be measured.

  At this time, as in the above-described embodiment, the beam splitter is selected so that the measurement light to all the substrates (substrates) S has the same intensity. That is, in order to make the measurement light directed toward the five substrates (substrates) S equal, the beam splitter is directed to the 20% substrate (substrate) S side at the first beam splitter (BS1) 165a. Use something. Similarly, of the 80% transmitted through the first beam splitter (BS1) 165a, a beam in which the same 20% measurement light as the first beam splitter (BS1) 165a is directed to the substrate (substrate) S (substrate) S side. A splitter is used, and the same ones are sequentially used. As a result, the last 20% measurement light is irradiated toward the substrate (substrate) S side also at the last total reflection mirror 165e. On the light receiving side, a beam splitter having a configuration opposite to that on the emission side is used. By configuring as described above, the optical path switching shutters 100a to 100c are not necessary.

  More specifically, the first beam splitter (BS1) 165a and the fifth beam splitter (BS5) 166a are 20%, the second beam splitter (BS2) 165b and the sixth beam splitter (BS6) 166b are 25%, The beam splitter (BS3) 165c and the seventh beam splitter (BS7) 166c are 33.3%, and the fourth beam splitter (BS4) 165d and the eighth beam splitter (BS8) 166d are 50%.

Cases with more than 5 branches are also available. The relative light output is
1 branch 100%
2 branches 25%
3 branches 11%
4 branches 6.25%
5 branches 4%
Assuming an n-branch case, the relative light output is P = (100% / n) ^ 2.
Here, the first beam splitter 1 (BS1) is X1 = 100% -100% / n, Y1 = X1.
The first beam splitter 1 (BS1) uses Y1: X1.
Similarly, the second beam splitter 2 (BS2) uses X2 = 100% −100% / (n−1), Y2 = X2.
The third beam splitter 3 (BS3) becomes X3 = 100% -100% / (n-2), Y3 = X3.
Therefore, the i-th beam splitter i (BSi) is determined as Xi = 100% −100% / (n−i), Yi = Xi, i <n.

<Fourth embodiment>
FIG. 19 shows a fourth embodiment. As described above, the i-th beam splitter i (BSi) is determined as Xi = 100% −100% / (n−i), Yi = Xi, i <n. Is shown.
More specifically, the first beam splitter (BS1) and the fourth beam splitter (BS4) are 75%, the second beam splitter (BS2) and the fifth beam splitter (BS5) are 33.3%, and the third beam splitter. (BS3) and the sixth beam splitter (BS6) are 50%.

5 and 6 show another embodiment of the apparatus. FIG. 5 is a cross-sectional explanatory view similar to FIG. 2, and FIG. 6 is a partial cross-sectional perspective view of the rotating drum of FIG. . Also in this embodiment, the same material, the same member, the same arrangement, and the like as those in the above embodiments are denoted by the same reference numerals, and the description thereof is omitted.
In the present embodiment, an example in which the beam splitters 166a to 166d and the total reflection mirror 166e on the light receiving side are mounted in the cylindrical body 160 in the same manner as the rotating shaft 13a on the emitting side is shown. Further, the beam splitters 166a to 166d and the total reflection mirror 166e on the light receiving side are attached to the cylindrical body 160 by known means, but are attached so that the inclination can be adjusted. Further, an opening is formed in the cylindrical body 160 at a position corresponding to the optical path of the measurement light so as not to obstruct the measurement light to the beam splitters 166a to 166d and the total reflection mirror 166e on the light receiving side. In this embodiment, although the example which formed the opening is shown, it is also possible to comprise so that it may seal using the glass material which can permeate | transmit completely.
With this configuration, it is possible to arrange the light receiving side only by mounting the cylindrical body 160 in the vacuum vessel 11, and it is easy to mount, and the cylindrical body 160 is pulled out during maintenance. Adjustment, repair, etc. can be performed.

<Fifth Embodiment>
Next, a fifth embodiment shown in FIG. 7 will be described. In this example, the light receiving unit is in the same direction (or the same surface) as the light projecting unit, whereas the light receiving unit and the light projecting unit are on the opposite side as shown in FIG. It is an example. Also in this embodiment, the same material, the same member, the same arrangement, and the like as those in the above embodiments are denoted by the same reference numerals, and the description thereof is omitted.
In this example, the first beam splitter (BS1) 65a and the second beam splitter (BS2) 65b are 50% for reflection / transmission, and the total reflection mirrors 66c and 66k are dielectric mirrors with R> 99.9%. The beam splitter (BS3) 66l and the beam splitter (BS4) 66m are 50%. Basically, it is configured as shown in FIGS.
In this way, the light projecting unit and the light receiving unit can be configured to be provided in the opposite direction of the optical thin film forming apparatus or the position of the opposite surface. Needless to say, in this embodiment, it is needless to say that the configurations shown in the second to fourth embodiments and the drawings can be applied as much as possible.

FIG. 12 is a cross-sectional explanatory view similar to FIG. 2 showing another embodiment. In this example, the output side beam splitters 65a and 65b and the total reflection mirror 65c are arranged inside the rotation shaft 13a. The rotary shaft 13a is provided with a vacuum magnetic shield for maintaining a vacuum, and is configured to maintain a vacuum. Note that a window glass is disposed on the emission side to prevent intrusion of foreign matter and impurities. If comprised in this way, it will become possible to set it as the structure which does not arrange | position a dirt prevention shield in each beam splitter.

Claims (9)

An optical film thickness measuring device of an optical thin film forming apparatus provided with a rotary type substrate holding means,
A light projecting unit that projects measurement light from one side of the rotation axis of the rotary substrate holding means toward the inside of the substrate holding means;
A light receiving unit for receiving measurement light from the light projecting unit;
A plurality of internal beam splitters provided inside the substrate holding means and reflecting the measurement light projected from the light projecting unit to the substrate;
An internal light reflecting member that is provided inside the substrate holding means and totally reflects measurement light from the nearest internal beam splitter among the plurality of internal beam splitters;
A plurality of external beam splitters provided outside the substrate holding means and reflecting measurement light from the plurality of internal beam splitters toward the light receiving unit;
An external light reflecting member that is provided outside the substrate holding means and reflects measurement light from the internal light reflecting member toward the light receiving unit,
Measurement light reflected by the plurality of internal beam splitters and the internal light reflecting member is transmitted through the substrate, and then reflected by the plurality of external beam splitters and the external light reflecting member to be guided to the light receiving unit. An optical film thickness measuring device that receives measurement light.   The rotation axis of the substrate holding means is located in a hollow rotation shaft that forms the center of the substrate holding means, and the internal beam splitter and the internal light reflecting member are disposed in the rotation shaft, and the rotation 2. The optical film thickness measuring apparatus according to claim 1, wherein a wall surface of the shaft body is configured to allow the reflected measurement light to pass therethrough.   The optical film thickness measuring apparatus according to claim 1 or 2, wherein the measurement light reflected by the internal beam splitter and the internal light reflecting member has a substantially equal light amount.   The film thickness calculating part which calculates the film thickness of the thin film formed in the said base | substrate based on the said measurement light light-received by the said light-receiving part is provided. Optical film thickness measuring device.   The plurality of external beam splitters and the external light reflecting member are covered with a hollow housing, and a portion of the housing where the measurement light is incident is configured to pass the measurement light. Item 5. The optical film thickness measuring device according to any one of Items 1 to 4.   The optical film thickness measuring device according to claim 1, wherein a shutter device is provided between the plurality of external beam splitters and the external light reflecting member.   The optical film thickness according to claim 1, wherein the light projecting unit and the light receiving unit are provided in the same direction or on the same surface of the optical thin film forming apparatus. Measuring device.   The said light projection part and the said light-receiving part are provided in the position of the surface on the opposite side or the other side of the said optical thin film formation apparatus, The one side of Claim 1 thru | or 7 characterized by the above-mentioned. Optical film thickness measuring device. A substrate holding means capable of rotating around a rotation axis while holding the substrate disposed in the vacuum vessel;
A film raw material supply means for supplying a film raw material for forming a thin film in the vacuum vessel;
A rotary thin film forming apparatus for forming a thin film comprising a film forming process region for forming a thin film on the substrate,
A thin film forming apparatus using the optical film thickness measuring apparatus according to any one of claims 1 to 8.

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